This project is designed to systematically investigate a number of correlates of the dopamine hypothesis of schizophrenia in clinical studies. To this end a number of indices of dopaminergic function in schizophrenics will be assessed. These include: (1) apomorphine dysphoria threshold after slow IV infusion of apomorphine, (2) growth hormone response to 0.5 of apomorphine subcutaneously, (3) growth hormone response to 500 mg 1-DOPA po., (4) behavioral response and prolactin suppression after 0.4 mg/kg d Amphetamine po. These indices, once quantified, will then be correlated with the degree of behavioral improvement induced by haloperidol as documented by standard rating scales (BPRS and CGI) and by the dose of haloperidol at which improvement is seen and stable. Both these indices of treatment response will be used for correlational analysis with measurement of dopaminergic sensitivity obtained previously.